#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#include<string.h>
#include<assert.h>
char* my_strcat(char*dest,const char*source) {
	char *p= dest;
	assert(dest && source);
	while (*dest) {
		dest++;
	}
	while (*dest++ = *source++) {
		;
	}
	return p;
}
int main()
{
	char arr1[20] = "hello";
	char arr2[20] = "world";
	printf("%s", my_strcat(arr1, arr2));
	return 0;
}